1. Field of the Invention
The present invention is related to a key structure with reduced resonant noise. In particular, the present invention relates to a key structure that has less noise during operation.
2. Description of Related Art
The manufacturing technology of the keyboard has continuously developed toward the goal of thinning the height. All elements of the keyboard therefore are closer and closer. However, providing enough pressing stroke (traveling distance) for the keycap is also required. The distance used to reduce noise has been sacrificed in the structural design, and the keycap is pressed directly to hit the conductive film and the base plate under the conductive film.
According to a test of a conventional keyboard of a notebook, a position being 26 cm high above the keyboard has a noise about 60 db when hitting a keycap. Based on the human factors standard, such a value for noise is enough to become an interference for anyone nearby.
To explore the source of shrill noise when hitting the keyboard, one crucial reason is the metal plate in the keyboard which causes a high-frequency noise when being hit. Besides, after the keycap is pressed down, there is an almost sealed space formed between the keycap and the conductive film above the base plate, which is like a small resonance chamber, so as to provide a resonant effect and amplify the noise.
Therefore, it is desirable to propose a novel key structure to overcome the above-mentioned problems.